I'd say that your heat bed is now scrap, it should be removed immediately and never used again!
The questions I'd ask include:
What sort of heat bed is it?
Are you sure you wired it properly?
Were the soldered-on wires nice and tidy, and not contacting any other track on the heat bed?
Did it look scratched, marked or badly bent when you installed it? (Note: PCB heatbeds do usually come very slightly curved)
Was there anything under the heat bed that might have contacted it as it moved?
Apart from that - it might simply have been a faulty heat bed.